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Fuel solenoid (diesel)

Posted: 28 Jul 2026, 12:55
by therealchrisgray
Hi all, me again

I've just been through the drama of replacing glow plugs, after tracing a fault that was blowing the 50A fuse. Now the fuel solenoid is acting up.

Replacing the glow plugs was a horrible fiddly job, and I had to remove the high pressure fuel lines to get access. I disconnected the fuel solenoid wire at the same time, to avoid accidentally snagging it.

All good, fuse no longer blowing, relay clicking, power to the bus bar, no shorts, dash board light came on. So I refitted the fuel lines and solenoid wire, turned the key ... and no glow plug light. Solenoid wire got very hot.

I dosconnected the solenoid wire, and it's receiving 12v with the key on. No problem.

I tested the solenoid in situ (disconnected) and got 15ohms resistance, which the AIs tell me is acceptable. But you guys are probably a lot smarter.

My understanding is I need to bleed the fuel lines, and I wondered if that's part of the problem. But how do I bleed the lines if the solenoid is not functioning?

Do I just buy a new solenoid? Or is there more to this?

Thanks

Re: Fuel solenoid (diesel)

Posted: 28 Jul 2026, 14:32
by The Hairy Camper
Well done for replacing the plugs, I did mine with the fuel lines in place and it was a tedious job.

Glad you have made some progress. Is the pump solenoid clicking when it gets 12v? Even with the solenoid installed, you should be able to hear it click when you give it 12v. That's a good indication that it's still working.

The guy who rebuilt my pump said it is best to stick with an original solenoid if you can.

Not sure why the solenoid wire is getting very hot though. Hopefully someone else will have an idea?

Re: Fuel solenoid (diesel)

Posted: 28 Jul 2026, 16:09
by therealchrisgray
Problem solved, mostly!

All the wiring is old, and the wire to the solenoid was earthing through the insulation to any bit of bare metal it was touching. Wrapped it in a load of insulation tape for now, bled the fuel lines, and it started right up.

I think I'm going to need a new wiring harness, but it's running and no mystery still to solve.

Thanks for the input!

Re: Fuel solenoid (diesel)

Posted: 28 Jul 2026, 17:37
by The Hairy Camper
Well done. Enjoy using your van this summer :D